Check this if you want to use O2 Priority Monents on Giff Gaff or Tesco Mobile (Android only)

I thought this might be handy for members on Giff Gaff and Tesco Mobile. It's an older version of O2's Priority Moments app which allows customers on the respective networks to install and activate the app using their regular Giff Gaff / Tesco number. No O2 sim required with this older version of the app. Newer versions of the app available from Google Play have since seen this loophole closed.

Simply download the apk file and transfer it onto your sd card and install from there.

Remember not to update the app otherwise it'll stop working and you'll have to reinstall..